Rivoli Roofing is considering mutually exclusive Projects A and B, which have the following cash flows: Year Project A Cash Flow Project B Cash Flow 0 $300 $420 1 30 110 2 50 80 3 50 100 4 60 60 5 90 60 At what cost of capital would the two projects have the same NPV? a. 9.54% b. 7.30% c. 8.61% d. 6.60%